The present invention relates generally to a system for automatically controlling movement of an unmanned vehicle and method therefor, particularly applicable to an unmanned transportation system in a factory or warehouse.
Recently, a great many unmanned vehicles have been produced which follow prearranged orbits or guide paths built into the floor, for example in factories or warehouses, in order to automatically transport loads. Since the steering is controlled in accordance with prearranged programs, changes in the vehicle course can be made only by modifying the programs. In addition, the intervals of acceleration or deceleration of such vehicles are determined by the driving torque of a motor serving as the prime mover. Since the driving torque is also controlled in accordance with the prearranged programs, the acceleration control can be altered only by changing the program.
A communication terminal comprising, e.g., a radio transceiver or opto-electrical communications equipment is provided at each point along the track at which such unmanned vehicles may change direction, accelerate, decelerate, or stop. In addition, a general control computer (also called host computer) located at an operation center uses these communication terminals to issue various commands to each vehicle to carry out steering adjustments, accelerate or decelerate the vehicle, or stop the vehicle using an identification code for each vehicle. A controller installed on each vehicle carries out the course corrections or speed adjustments (acceleration, deceleration or stop) in accordance with the commands issued by the general control computer.
Although it is possible to control the movements of a plurality of such unmanned vehicles along a plurality of routes in the above-described conventional system since commands can be issued arbitrarily to each vehicle by means of the individual identification codes, the communication equipment located on the ground and on the vehicles and the controllers installed on the vehicles is exceedingly complex and expensive. In addition, there are various problems in the above-described control method. Particularly when the routes followed by the vehicles are to be changed or expanded, large-scale construction including installation and/or movement of communication equipment on the ground, program modification and expansion of the processing capacity of the controllers installed on the vehicles are required. The communication between the vehicles and general control computer is rather complex so that reliability cannot be assured even when special communications hardware is employed.